captchaI am a captcha newbie so I do not how sophisticated my idea for a captcha would be.
Using PHP:
Define a seed string of upper and lower case letters, plus numbers.
Generate a random string of 512 or 1024 or whatever length long.
Divide the length of the generated string by the number of characters in the captcha string - call this number 'Nindex'
Generate a random number between 0 and Nindex.
Use this new random number as an index into the random string.
From that index, pick out the number of characters required for the catcha string.
Now display these characters vertically for the form user to re-enter.
How easily could you experts break this captcha ?
Regardshttp://sla.ckers.org/forum/read.php?7,24673,24673#msg-24673
Tue, 31 Mar 2015 17:06:06 -0500Phorum 5.2.15ahttp://sla.ckers.org/forum/read.php?7,24673,51922#msg-51922Re: captchahttp://sla.ckers.org/forum/read.php?7,24673,51922#msg-51922
winwalkRobots/Spiders/CAPTCHAs, oh myTue, 24 Sep 2013 04:03:52 -0500http://sla.ckers.org/forum/read.php?7,24673,24674#msg-24674Re: captchahttp://sla.ckers.org/forum/read.php?7,24673,24674#msg-24674
In short, it is not necessarily the algorithm you use to generate the string, but how you display the characters to the user that can ultimately determine the strength of the CAPTCHA.]]>Matt PressonRobots/Spiders/CAPTCHAs, oh myMon, 22 Sep 2008 08:12:29 -0500http://sla.ckers.org/forum/read.php?7,24673,24673#msg-24673captchahttp://sla.ckers.org/forum/read.php?7,24673,24673#msg-24673
Using PHP:
Define a seed string of upper and lower case letters, plus numbers.
Generate a random string of 512 or 1024 or whatever length long.
Divide the length of the generated string by the number of characters in the captcha string - call this number 'Nindex'
Generate a random number between 0 and Nindex.
Use this new random number as an index into the random string.
From that index, pick out the number of characters required for the catcha string.
Now display these characters vertically for the form user to re-enter.